These unusual trees have a rather small distribution. Their range includes California, Nevada, Utah, and Arizona's Mojave Desert. They only grow between 2,000 and 6,000 feet in elevation.
Joshua trees were named after the biblical figure Joshua, who led Israel as their leader. The tree was chosen because it grew near where Moses had instructed his people to camp when they reached the land of Canaan. It is believed that Moses may have been pointing out this particular species of cactus for its usefulness in providing food and shelter for humans and animals during their long stay at Mount Sinai before being sent back home.
Today, many areas where Joshua trees used to be found have been developed into towns or farms. Since these trees require very dry conditions in which to grow, they are often destroyed when water is needed for other things such as crops or cities. However, there are several places where they have been protected by being placed on federal or state lands. These include Death Valley National Park, Zion National Park, and Sequoia & Kings Canyon National Parks.
Although the Joshua tree is now rarely seen in populated areas, people still know them from photographs because of their unique appearance. The spiky white branches can reach up to 100 feet high, with each branch bearing 3-5 flat brown pods filled with tiny white flowers in springtime.
The Joshua tree is a solid sign that you are in the Mojave Desert, although it may also be seen growing next to a saguaro cactus in western Arizona's Sonoran Desert or mixed with pines in the San Bernardino Mountains. These trees were named after Captain Joshua Aten, who traveled through this area with his crew in 1827. He noted in his journal that the trees seemed to be dying out, but then made the observation that they revived themselves each year. Today, scientists believe that heat, drought, and overgrazing are the main factors causing the trees' demise.
The Joshua tree is a large tree, usually reaching 30 feet in height. It has thick, leathery dark green leaves that measure up to 12 inches long. The tree produces red flowers between April and June, followed by orange-yellow fruit that contain one seed. This fruit is edible when raw but not recommended for cooking because of its acidic nature. People have used the wood of the Joshua tree for fuel, tools, and weapons because it is hard and durable. Growing numbers of people are helping protect the Joshua tree by allowing it to grow in their backyards as an urban forest project called TreePeople.
Boulder County is one of only two places in California where the tree is protected by law.
The Joshua tree's trunk is typically one to three feet (0.3 to 0.9 meters) in diameter. Joshua trees may reach heights of 20 to 70 feet (6 to 21 meters), but seldom exceed 40 feet (12 meters). Joshua trees are desert plants that are most typically seen in the southwestern United States' Mojave Desert.
The name "Joshua tree" comes from the Bible character Joshua, who according to the Book of Joshua commanded all the people living in the land he conquered to cut down some large trees and give them as a sign against attacking armies.
Modern-day Joshua trees are estimated to be between 300 and 500 years old. The trunk of a mature tree can be 30 to 50 feet high with a base diameter of up to 9 feet. At the top of this spiral shape is a thick crown of green leaves which measure up to 18 inches long. The tree's grayish bark is covered with a white powder called salt that collects during dry seasons.
There are two varieties of Joshua tree: var. Joshua and var. Filipes. Var. Joshua has spines along its branches while var. Filipes has smooth trunks. Both varieties contain an unusual compound called mannitol which is used by some animals for food poisoning.